The original aim of this project was to define the effect of puberty on the etiology and progression of diabetic nephropathy. During the course of this project we identified cardiovascular abnormalities (increased left ventricular mass index, cardiac contractility and blood pressure) which were associated with increased glomerular filtration rate and micro- albuminuria (preclinical manifestations of diabetic nephropathy) suggesting that the complications of IDDM in these two organ systems develop in a parallel fashion. Due to these findings we established the following specific aims: 1) to determine the sequence of appearance and interrelationships in the early and the lage stages of preclinical cardiac, renal and hypertensive disease in young subjects with IDDM; 2) to identify the role of variables potentially associated with the evolution and progression of changes in cardiac, renal and hypertensive disease; and 3) to determine whether developing cardiac dysfunction is associated with evidence of a diffuse cardiomyopathy or the early onset of coronary artery disease in adolescents and young adults with IDDM. In addition, the information generated in this project resulted in the development and funding of project #486: "Coronary Atherosclerosis in Early Insulin- Dependent Diabetes Mellitus".